38. The beauty of sub-antimicrobial dosing

Doctor Jacob here, and today we're talking about the beauty of sub-antimicrobial dosing of antibiotics in the treatment of acne. Also, this works for the treatment of rosacea, which is a closely related condition where certain tetracycline-based antibiotics can really help you. That's an aside, back to acne.

As was mentioned in the previous episode, there can be some issues with the long-term use or even short-term use of antibiotics in the treatment of acne. We worry bacterial resistance, in which these antibiotics will no longer work in the community because of their widespread use for the treatment of acne, which is certainly a problem because there are a limited number of antibiotics available. But beyond that, at full doses, antibiotics kill bacteria which are helpful to the body, especially in the intestine and also in the vaginal tract, too. So by killing these bacteria we can induce side effects of diarrhea or loose stools, stomach cramps and sometimes yeast infection in women. So antianaerobic antibiotics have these issues and also with repeated courses have been shown to be linked to inflammatory bowel disease such as ulcerative colitis or Crohn's disease, so we really don't want our patients at risk for these conditions. We don't want to increase risk because these are chronic conditions, they're not curable and they can interfere with patients' lives.

So the thought is by giving a very low dose of antibiotic - it's usually doxycycline, but can be minocycline too - typically a very low dose of doxycycline such as 20 mg twice daily, or a 40 mg once daily dose we can get the anti-inflammatory beneficial effects of the antibiotic in the treatment of acne but without killing the bacteria, so there's no risk of antibiotic resistance, it doesn't cause this inflammatory bowel disease or yeast infection, or antibiotic associated diarrhea or toxic megacolon, clostridium difficile colitis - none of these problems can come about, because the dose is so low it actually doesn't kill bacteria, but it has anti-inflammatory properties. That's the beauty of sub-antimicrobial dosing.

Typically when I write for this for acne, I write the doxycycline 20 mg twice a day, or more commonly the 40 mg once daily of doxycycline. That goes by the brand name Oracea, and we've referred to that in some previous episodes as well.

An example of the appropriate use of antibiotic therapy would be a patient with an inflammatory type acne, because again antibiotics do not unclog pores, so an inflammatory acne such as papular and pustular, or even nodulocystic acne. Maybe for the first month I wouldn't give a full dose of antimicrobial therapy to get things quickly under control, if that rapidity is desired by the patient, and afterwards if we're doing good we can drop down to a sub-antimicrobial dose.

Of course, there are alternate treatment strategies such as Accutane or isotretinoin as the generic name goes, but for getting things under control really quickly, for severe cases of acne or even moderate cases, oral antibiotics are very, very useful, which is why they're so widely prescribed.

I'm Doctor Jacob, don't forget about sub-antimicrobial dosing, especially for the long-term use of oral antibiotics for acne. We'll see you next time.